In recent years, there has been known a method for giving a presentation by using a whiteboard as a projection screen and projecting an image on the white board. Using a projector this way allows the presenter to directly write comments and underlines with a marker pen on the whiteboard and create a table on the whiteboard for organized discussion or other purposes in the course of the presentation.
Japanese Patent Publication No. 2004-198858 discloses a projection apparatus in which a built-in or removable memory stores a template image formed of a plurality of ruler lines and when the projector is in use, the stored template image is projected on a screen in response to predetermined operation. Since the projection apparatus described in Japanese Patent Publication No. 2004-198858 can project the template image formed of a plurality of ruler lines on the screen, the user does not have to directly write a table with a maker pen on the screen, resulting in improvement in workability.
The projector described in Japanese Patent Publication No. 2004-198858, however, usually projects the template image formed of ruler lines over the entire projection area. Since the template image is thus enlarged and projected over the nearly entire surface of the whiteboard, the user cannot write a memo, a minute, or other notes on the whiteboard as long as the template image is projected. That is, the user cannot arbitrarily set the ratio of the template image to the projection area.